DE 33 15 419 A1 discloses a conveying unit in a thermoform packaging machine, which is also referred to as clamp chain and which is used for guiding and conveying a material web. The clamp chain comprises a link chain with chain links and a plurality of clamping jaws, fixed clamping jaws being connected by means of a riveted joint with a bolt to a respective chain link. The movable clamping jaw has a bore accommodated in a flange sleeve provided on the fixed clamping jaw, so that the movable clamping jaw can be held and also moved relative to the fixed clamping jaw. A compression spring arranged between the fixed and the movable clamping jaw provides a biasing force in the direction of the closed position at which the material web is clamped between the movable and the fixed clamping jaw.
The known clamp chain has, on the one hand, the drawback that the fixed clamping jaws must be connected to the chain links and that this requires a considerable mounting effort. On the other hand, a few gaps exist between the chain link and the fixed clamping jaw as well as between the chain links themselves, said gaps being difficult to clean and therefore disadvantageous for hygienic reasons.
DE 103 51 125 A1 discloses a force-transmitting hybrid chain for a completely different technical field, i.e., for the field of internal combustion engines.